An inspection-specific drone equipped with state-of-the-art imaging systems that reduces need for expensive access methods and traffic control was estimated to cost $15,000 to $40,000 to purchase or $300 to rent.

MnDOT assessment of drone-use as part of a risk- based approach to bridge inspection realizes safety, cost and quality improvements.

Made Public Date

The Minnesota Department of Transportation (MnDOT) is utilizing drones to collect and process large amounts of data during bridge inspections with the goal of improving the quality of bridge inspections and improving safety for both inspectors and the traveling public.

In the summer of 2015 and 2016, a research team implemented Unmanned Aerial Systems (UAS) technology on 39 bridges including a wide range of bridge sizes, types, and locations to demonstrate the benefits and challenges of employing UAS on a large scale. Applications included using the drones to survey confined space inspections in steel and concrete box beams and pier towers, as well as inspections between beams for multi-girder bridges and bearing inspection for beam bridges.

Data was collected primarily from an imaging payload intergraded into the UAS body. Case study inspection reports that included a cost analysis were compiled for 12 bridges representative of various use cases.

The following tables compare the costs between traditional inspection and access methods with UAS assisted inspection.

Capital Costs:


Under Bridge Inspection Vehicle:
Purchased: $500,000 to $1,000,000
Rental: $3,000/day

Inspection-specific drones equipped with state of the art imaging devices:
$15,000 to $40,000
Rental: $300/day


Inspection Costs:




Cost Assumptions Cost
Bridge Inspection Team Leader $150/hour
Assistant Bridge Inspector $120/hour
Under Bridge Inspection Vehicle with Operator $3,000/day
Drone Equipment $300/day
Post Processing Engineer $120/hour
Low Speed Lane/Shoulder Closure $2,000/each
Mobile Lane/Shoulder Closure $1,500/each
High Speed Lane/Shoulder Closure $2,500/each




Bridge Structure ID Traditional Inspection Cost UAS Assisted Inspection Cost
19538 $1,080 $1,860
4175 $15,980 $13,160
27004 $6,080 $4,340
27201 $2,160 $1,620
MDTA Bridges $40,800 $19,800
2440 $2,160 $1,320
27831 $2,580 $540
82045 $2,660 $1,920
62080 $2,580 $1,350
62090 $2,410 $1,570
62504 $3,660 $1,020
82502 $3,240 $2,400